The pattern_capture token filter, unlike the pattern tokenizer,
emits a token for every capture group in the regular expression.
Patterns are not anchored to the beginning and end of the string, so
each pattern can match multiple times, and matches are allowed to
overlap.

Multiple patterns are required to allow overlapping captures, but also
means that patterns are less dense and easier to understand.

Note: All tokens are emitted in the same position, and with the same
character offsets. This means, for example, that a match query for
john-smith_123@foo-bar.com that uses this analyzer will return documents
containing any of these tokens, even when using the and operator.
Also, when combined with highlighting, the whole original token will
be highlighted, not just the matching subset. For instance, querying
the above email address for "smith" would highlight: